rat model o”>American Journal of Emergency Medicine (2012) 30, 1176-1182

Original Contribution

Effects of terlipressin in a rat model of severe uncontrolled hemorrhage via Liver injury

Basak Bayram MD ^a,?, Nil Hocaoglu MD ^b, Ridvan Atilla MD ^a, Sule Kalkan MD ^b

^aSchool of Medicine, Department of Emergency Medicine, Dokuz Eylul University, Izmir, Turkey

^bSchool of Medicine, Department of Medical Pharmacology, Dokuz Eylul University, Izmir, Turkey

Received 4 July 2011; revised 24 August 2011; accepted 8 September 2011

Abstract

Background: Animal experiments and clinical studies have shown that vasopressin infusion in cases of uncontrolled hemorrhagic shock is a promising treatment. However, there are only a few studies regarding the application of terlipressin in hemorrhagic cases. This study was designed to evaluate the effects of terlipressin vs controlled fluid resuscitation on Hemodynamic variables and abdominal bleeding in a rat model of uncontrolled hemorrhage via liver injury.

Methods: A total of 21 average weight 250 +- 30 g Wistar rats were used. A midline celiotomy was performed, and approximately 65% of the median and left lateral lobes were removed with sharp dissection. After creation of the liver injury, rats were randomized into 1 of 3 resuscitation groups, the control group, lactated Ringer‘s (LR) group, and terlipressin group, with 7 rats in each group. Blood samples were taken from rats for arterial blood gas analysis. At the end of the experiments, free intraperitoneal blood was collected on preweighed pieces of cotton, and the amount of free blood was determined by the difference in wet and dry weights.

Results: In response to resuscitation, the terlipressin group demonstrated a significant elevation in mean arterial pressure (MAP). Blood loss was greater in the LR group compared with the control group (12.8 +- 1.9 mL vs 8.2 +- 0.7 mL, P b .05). At the end of the experiments, 5 rats in the control group, 5 in the LR group, and 2 in the terlipressin group died. The average survival rates were 28.6%, 28.6%, and 71.4%, respectively.

Conclusions: Compared with the control group, intravenous terlipressin bolus after liver injury contributed to an increase in MAP and survival rates without increasing abdominal bleeding.

(C) 2012

Introduction

* Corresponding author. Tel.: +90 505 525 10 75; fax: +90 232

2590541.

E-mail addresses: [email protected] (B. Bayram), [email protected] (N. Hocaoglu), [email protected] (R. Atilla), [email protected] (S. Kalkan).

Deaths due to trauma are increasing worldwide. Five million people died of traumatic injuries in 2000, and above 8 million deaths from trauma are estimated for 2020 [1]. Approximately 30% of these deaths are due to hemorrhagic shock. However, the most effective treatment method for patients with uncontrolled hemorrhagic shock is still

0735-6757/$ – see front matter (C) 2012 doi:10.1016/j.ajem.2011.09.007

controversial [2,3]. The traditional treatment method for patients with trauma requires an initial fast Bolus injection and later additional fluid supplementation; however, various studies have shown that this treatment method increases the rate of deaths in patients, especially those with abdominal trauma [1,4,5]. Many new studies have revealed that controlled hypotension and delayed resuscitation increase survival rate of patients, especially patients with penetrating abdominal trauma [5,6].

The controversial strategy regarding the most appropriate fluid resuscitation for patients with uncontrolled hemor- rhagic shock has led to the investigation of alternative treatment methods for these patients. The results of vasopressin infusion, which is one of the alternative Treatment methods, are promising [6,7]. Animal experi- ments and clinical studies have revealed that the application of vasopressin infusion in cases of uncontrolled hemor- rhagic shock because of penetrating lung injury reduces splanchnic blood flow and bleeding [6-9]. Another effect of vasopressin is that it directs blood flow from the subdiaphragmatic area to the brain and heart.

Terlipressin (Tri-glycyl-lysine-vasopressin) is a long- acting Vasopressin analogue, which was produced for the pharmacologic treatment of esophageal Variceal hemorrhage [10]. Clinical and experimental studies have also revealed that terlipressin leads to a significant improvement in mean arterial blood pressure in patients with catecholamine- resistant septic shock [11]. However, there are only a few studies regarding the application of terlipressin in human beings in hemorrhagic cases, and a randomized controlled study of this treatment method has yet been conducted. This study was designed to evaluate the effects of terlipressin vs controlled fluid resuscitation on hemodynamic variables and abdominal bleeding in a rat model of uncontrolled hemorrhage via liver injury.

Materials and methods

This study was approved by the Dokuz Eylul University School of Medicine Animal Use Committee (Izmir, Turkey). This controlled experimental study was performed using 21 adult male Wistar rats weighing 250 +- 30 g. Animals were maintained in controlled environmental conditions with a 12- hour light/dark cycle and fasted overnight with free access to water before the experiments.

Each rat was anesthetized by intraperitoneal injection of urethane/chloralose (500 and 50 mg/kg, respectively) [12]. The trachea was cannulated caudal to the larynx using an 8-gauge nasogastric cannula for spontaneous breathing. The right Common carotid artery was cannulated with a polyethylene cannula (PE 50 outside diameter mm [in] 0.97 [0.038] inside diameter mm [in] 0.58 [0.023]) containing heparinized saline (100 U/mL) for blood pressure measurement. The left external jugular vein was

cannulated with the same type of polyethylene cannula for the administration of normal saline , Lactated Ringer’s (LR) solution or terlipressin. Mean arterial pressure (MAP), heart rate (HR), and survival time were recorded on a data acquisition system (Powerlab/8SP Data Acqui- sition System, AD Instruments, Castle Hill, Australia) by a transducer (MLT844 Physiological Pressure Transducer, Interlab LTD, Istanbul, Turkey) during the experiment.

Arterial blood samples (0.2 mL) were obtained with an injector containing heparinized saline (20 IU/mL) for blood- gas analysis (pH, pO₂, pCO₂, HCO₃, Base deficit, lactate, hematocrit, and hemoglobin) via an arterial cannula in the right common carotid artery at the end of the stabilization period and 30 and 90 minutes after Hepatic injury. Volume (0.6-1.2 mL) was replaced intravenously with NS. The samples were analyzed immediately in a blood-gas analyzer (Irma TruPoint blood analysis System, ITC Med, CA, USA). During the experiment, body temperature was kept at 37?C with the use of a desk lamp.

After the cannulation procedure, the animals were allowed to stabilize for 15 minutes. Then, baseline measurements were performed. Based on the consecutive studies of Matsuoka et al [13,14], at the end of the stabilization period, hepatic injury was performed. For hepatic injury, a midline celiotomy was performed, and approximately 65% of the median and left lateral lobes were removed with sharp dissection. Then, the incision was quickly closed using a stapler, and the rats were randomized into 3 groups (n = 7 for each group). The resected portions of the liver were weighed. Although control animals (group 1) received only an Intravenous bolus of NS (same volume as terlipressin, approximately 0.5 mL), treatment groups received a bolus of LR (4 mL/kg) in group 2 or terlipressin (50 ug/kg) in group 3 (Table 1). Lactated Ringer’s solution was given (infusion rate, 2 mL/kg per min) to maintain a mean arterial blood pressure of 40 mm Hg for all groups, if required. Continuous supplemental LR infusion was then given for 75 minutes (until the 90th min). The MAP and HR were recorded for each rat during the 90 minutes.

Individual time profiles of the MAP and HR were calculated on the basis of change from the baseline value. In addition, blood-gas analysis, hepatic volume, and the amount of hemorrhage were compared among the 3 groups.

At the end of the experiment, the free-flowing blood in the peritoneal cavity was absorbed using cotton and then weighed to determine the effect of LR and terlipressin on Abdominal hemorrhage. The weight of the absorbed blood was deduced from the dry weight of the cotton, and then, the amount of intraabdominal hemorrhage was calculated. Each variation of 1 g in weight was accepted as equal to a blood loss of 0.9 mL [15].

The starting moment of liver injury was accepted as the zeroth minute ([15]; Table 1). At the end of the experimental protocol (in the 90th min), surviving rats were killed via cervical dislocation.

Table 1 Experimental protocol

Stabilization

Surgical Zeroth

bolus administration

LR infusion

procedure minute

Urethane and chloralose 15 min (500 and 50 mg/kg, intraperitoneally)

~15 min

Liver injury Group 1 (control) (normal

saline, same volume of terlipressin)

Group 2 (LR) (Lactated Ringer’s solution, 4 mL/kg) Group 3 (terlipressin)

(terlipressin, 50 ug/kg)

Follow-up period

If necessary, 90 min (0.4 mL/min, during

75 min)

Blood gas analysis-1 Blood gas analysis-2

and 3 (0th and 90th min)

Drugs

Urethane and ?-chloralose were obtained from Sigma Chemical Company (St. Louis, Mo) and prepared as stock solutions in distilled water of 50 and 40 mg/mL, respectively. Terlipressin (terlipressin acetate [Glypressin(R). Ferring Pharmaceuticals Ltd., Malmo, Sweden]) was obtained from a local drugstore and was dissolved in normal saline at a concentration of 1 mg/5 mL for bolus injection.

Statistical analysis

Statistical analyses were performed using percent changes in the MAP, HR, and blood-gas analysis (pH, pCO₂, HCO₃, base deficit, lactate, hematocrit, and Hemoglobin levels). The data within groups were evaluated using Student t test for paired data. To analyze the differences among groups, analysis of variance and Tukey-Kramer multiple comparison tests were performed. Kaplan-Meier test was performed for survival rates. All data are presented as the mean values +- standard error of the mean (SD). For all studies, P values of less than .05 were considered to be statistically significant.

Results

At the beginning of the experiment (in the stabilization period), no significant differences were found between the MAP, HR, and body weights of rats in all groups (Table 2). In addition, at this time, no significant differences were observed between the values of pH, pO₂, pCO₂, HCO₃, base deficit, lactate, hematocrit, and hemoglobin levels (Table 3).

Table 2 Mean arterial pressure, HR, and body weight of each of the three groups at the beginning of the experiment
	Control	LR	Terlipressin	P
Mean arterial	119.4 +- 4.2	108.8 +- 4.4	111.0 +- 4.8	N.05
pressure HR	428.1 +- 16.1	407.9 +- 23.2	413.7 +- 18.9	N.05
Body weight	259.7 +- 3.9	263.1 +- 8.3	252.3 +- 3.8	N.05

The mean weight of the extracted liver for all groups was

2.4 +- 0.1 g, and no significant difference was observed between the extracted liver weights of each of the 3 groups (P N

.05). The mean ratio of the extracted liver weights for all groups to the total weight of the left lobe was 57.8% +- 1.4%, and no significant difference between the ratios of the extracted liver weights for each of the 3 groups to the total weight of the left lobe was found (P N .05). Finally, there was no significant difference between groups in the ratio of the extracted liver weights to the body weights of the rats (P N .05).

The MAP decreased to 42.8 +- 10.5, 31.9 +- 2.9, and 41.9 +-

3.9 mm Hg for the control, LR, and terlipressin groups, respectively, after liver injury. No significant difference was found between the groups in the MAP after liver injury (P N

.05). Normal saline (NS) bolus administration did not improve the MAP reduction induced by liver injury. After LR bolus administration, the MAP reduction persisted, which was statistically significant (P b .001). In the terlipressin group, although terlipressin bolus administration did not significantly increase the MAP, there were significant increases 5, 10, and 15 minutes after terlipressin bolus

administration (P b .01, P b .01, and P b .05 for 5, 10, and 15 minutes, respectively; Table 4). Liver injury-induced decrease in MAP continued between 15 and 45 minutes after discontinuing terlipressin bolus administration in terlipressin group (P N .05; Table 4). There was no statistically significant difference in the MAP among the groups during the entire experimental protocol (P N .05; Fig. 2).

Liver injury did not cause significant changes in the HR in any group (P N .05). In addition, there was no significant improvement in the HR after NS, LR, or terlipressin was administered (P N .05; Table 3). Finally, there was no statistically significant change in the HR among the groups during the experiment (P N .05; Fig. 1).

When the percentage in variation in the MAP after liver injury was examined, a significant increase was recorded in the 4.6 +- 0.9th minute in the terlipressin group. This increase was equal to 190.5% +- 23.1% of the MAP after liver injury (Fig. 2).

At the end of the experiment, when the blood gas parameters (pH, pO₂, pCO₂, HCO₃, base deficit, lactate, hematocrit, and hemoglobin levels) of the groups were

Control		LR		Terlipressin	P ?
pH
Initial	7.4 +- 0.0	7.3 +-	0.0	7.3 +- 0.0	N.05
End of the experiment	7.2 +- 0.1	7.2 +-	0.1	7.0 +- 0.1	N.05
pO2
Initial	96.9 +- 15.9	94.4 +-	12.9	75.0 +- 3.3	N.05
End of the experiment	62.5 +- 15.1	71.8 +-	10.0	109.5 +- 13.3	N.05
pCO2
Initial	27.2 +- 3.7	28.3 +-	2.9	34.9 +- 4.7	N.05
End of the experiment	44.5 +- 10.6	42.5 +-	8.0	31.6 +- 5.3	N.05
HCO3
Initial	15.4 +- 2.4	14.5 +-	0.9	18.0 +- 2.1	N.05
End of the experiment	14.4 +- 2.3	14.3 +-	2.2	8.3 +- 1.3	N.05
Base deficit
Initial	-8.3 +- 2.2	-9.7 +-	0.7	-6.9 +- 1.6	N.05
End of the experiment	-13.3 +- 2.2	-13.8 +-	2.8	-21.3 +- 2.1	N.05
Lactate
Initial	1.1 +- 0.1	1.2 +-	0.2	1.4 +- 0.2	N.05
End of the experiment	4.6 +- 1.2	6.8 +-	1.1	7.7 +- 1.4	N.05
Hematocrit
Initial	29.7 +- 6.0	24.7 +-	3.3	36.9 +- 4.1	N.05
End of the experiment	23.0 +- 4.4	16.7 +-	4.1	14.1 +- 3.4	N.05
Hemoglobin
Initial	11.8 +- 1.5	8.9 +-	1.3	12.6 +- 1.4	N.05
End of the experiment	9.6 +- 1.4	9.1 +-	0.2	8.3 +- 2.1	N.05
a The blood gas, hematocrit, lactate, and hemoglobin values found independently of time at the end of the experiment. * P N .05 for NS-LR, LR-terlipressin, and NS-terlipressin when all groups were compared.

compared, no statistically significant changes were found (P N .05; Table 3).

Table 3 Blood gas, lactate, hematocrit, and hemoglobin level values of each of the 3 groups at the beginning and end of the experiment ^a

When the amounts of abdominal hemorrhage were evaluated, the amount of hemorrhage was significantly higher only in the LR group. The mean amount of hemorrhage was 8.1 +- 0.7 mL (31.2 +- 2.3 mL/kg) in the

control group and 12.8 +- 1.9 mL (47.6 +- 5.9 mL/kg) in the LR group. When the control group was compared with the LR group, a statistically significant difference was found (P b .05 for NS_mL and LR_mL). The mean amount of hemorrhage in the terlipressin group was 10.5 +- 1.3 mL (42.0 +- 5.4 mL/kg). No significant difference was found between the terlipressin and control groups (P N .05 for NS_mL and terlipressin_mL).

The need for fluid significantly decreased after 30 minutes in the terlipressin group compared with the LR group (average: 16.7 +- 5.9 mL in the LR group and 5.8 +-

1.9 mL in the terlipressin group for rats reaching 30-minute survival time).

In the 30-minute life analysis (1800 seconds) via Kaplan- Meier test, the survival rate was 28.6% (2/7) for the control group, 28.6% (2/7) for the LR group, and 71.4% (5/7) for the terlipressin group. The median survival times were 660, 1200, and 2550 seconds for the control, LR, and terlipressin groups, respectively. No statistically significant difference was observed between the survival rates of the control, LR, and terlipressin groups (P N .05; Fig. 3).

Discussion

In our study, we used an animal model to demonstrate the effect of terlipressin in hemorrhagic shock because of traumatic liver injuries. In the liver injury model developed by Matsuoka et al, 15% of the left median and lateral lobes was extracted, and then, the injury was induced. They achieved a survival rate of 87% in the shock period [12,13]. In the study by Holcomb et al [16], who modified the model created by Matsuoka et al, the median lobe was measured and extracted, and a survival rate of 50% was achieved at 30 minutes. However, 60% +- 6.7% of the median lobe was extracted, and the survival period was shorter in this study. In a study by Lu et al where the authors compared different values of MAP in uncontrolled hemorrhages, the survival rate of rats injected with the fluid having a target limit value of MAP of 40 mm Hg was increased. In addition, no increase in hemorrhage was observed in these rats compared with the group receiving normal fluid treatment [15]. Therefore, we chose 40 mm Hg as the target limit value

for resuscitation in our study.

In addition to previous studies in which bolus fluid treatments were used [12], there have also been studies in which intravenous infusion was used. However, it is not possible to administer high doses of fluid into human beings at this time despite the application of fluid resuscitation through wide vascular access. In the application widely used

140

22.45 +- 9.6

34.7 +- 5.9

38.4 +- 12.9

370.0 +- 48.0

357.5 +- 8.5

327.2 +- 39.9

120

30 min

Heart Rate (%)

100

80

60

18.2 +- 7.1

32.2 +- 9.4

40.7 +- 12.1

370.0 +- 39.0

370.0 +- 4.0

368.0 +- 32.3

40

20

25 min

0

Stab L.injury Bolus

Time (minute)

LR

Terlipressin

5

10

15

20

25

30

35

40

45

Control

Fig. 1 A graph depicting time vs the Percentage change in HR.

18.6 +- 7.4

24.9 +- 6.0

49.4 +- 11.5

368.5 +- 29.5

369.3 +- 6.7

398.6 +- 18.8

during the prehospital period in Europe, the initial fluid treatment administered in a dose of 2 mL/kg per min is applied for more than 10 minutes, and this dose is increased up to 8 mL/kg per min in the event that the target blood pressure is not achieved [9]. Therefore, in our study, additional fluid treatments were applied via infusion.

15 min

20 min

21.1 +- 4.9

25.0 +- 3.4

44.2 +- 13.5

367.0 +- 16.0

378.8 +- 8.4

350.6 +- 27.0

In a Cochrane compilation of the randomized controlled studies regarding the fluid administration in patients with uncontrolled hemorrhage, it was concluded that no material evidence is available for early and/or large volume fluid administration in patients with uncontrolled hemorrhage [2]. In updated guidelines for trauma care, the initial bolus isotonic crystalloid infusion (2-3 L for adults, 20 mL/kg for children) and a later evaluation of the patient’s response are recommended for patients with hemorrhage [4]. In fact, the harmful effects of large volume fluid resuscitation have been demonstrated in many studies. Some experts even argue that no fluid should be administered to patients with uncontrolled hemorrhage during the prehospital period as long as the radial pulse can still be felt [17].

Bolus administration

5 min

10 min

26.1 +- 2.4

26.1 +- 3.7

37.5 +- 5.9

18.2 +- 0.4

25.6 +- 6.6

57.5 +- 10.0

18.4 +- 0.7

27.2 +- 7.1

61.3 +- 12.7

372.7 +- 20.5

359.2 +- 24.3

395.4 +- 19.1

384.0 +- 13.0

365.2 +- 16.2

366.7 +- 26.2

374.0 +- 11.0

345.8 +- 24.8

321.1 +- 33.7

Although we based our study on hypotensive resuscita- tion limits, no improvement was achieved in the survival rates via fluid resuscitation with LR compared with the control group. Likewise, additional fluid treatment failed to improve the vital signs in most of the rats. In the literature, it has been demonstrated that the most vital phase for patients with hemorrhage or in hemorrhagic shock is the diagnosis and Hemorrhage control stage [18]. The results of our study confirmed this conclusion. Although hypotensive resuscita- tion is a presurgical alternative treatment method in patients

Table 4 Changes in the MAP and HR values during the experiment

Baseline

Hepatic injury

119.4 +- 4.2

108.0 +- 4.4

111.0 +- 4.8

42.8 +- 10.5

31.9 +- 2.9

41.9 +- 3.9

428.1 +- 16.1

407.9 +- 23.2

413.7 +- 18.9

388.6 +- 27.2

369.9 +- 30.3

411.1 +- 17.9

180

Mean arterial pressure (mm Hg) Group 1 (control, normal saline) Group 2 (Lactated Ringer’s) Group 3 (terlipressin)

HR (beats per min)

Group 1 (control, normal saline) Group 2 (Lactated Ringer’s) Group 3 (terlipressin)

Mean Arterial Pressure (%)

160

140

120

100

80

60

40

20

0

Stab L.injury Bolus

Time (minute)

LR

Terlipressin

5

10

15

20

25

30

35

40

45

Control

Fig. 2 A graph depicting time vs the percentage change in the MAP.

Fig. 3 Time vs the variation in survival rates for each of the 3 groups.

with serious hemorrhage and in hemorrhagic shock, surgical hemorrhagic control is of top priority.

The development of full Cardiovascular collapse has serious negative effects on survival. In a study by Rosemurgy et al [19], none of the patients requiring cardiopulmonary resuscitation on-site or during transport survived. Therefore, the prevention of cardiac arrest development after trauma should be considered the primary goal in trauma care. The determination of hypotension in patients with hemorrhage due to trauma is an indication of mortality and morbidity, and the prevention of prolonged hypotension may be as important as the prevention of cardiac arrest.

Animal experiments and clinical studies have shown that vasopressin infusion in cases of uncontrolled hemorrhagic shock is a promising treatment [6,7,9]. In the hemorrhagic shock model developed by Lee and Chang [20], both vasopressin and terlipressin were shown to improve hemodynamic parameters and cytokine profiles, and terli- pressin is advantageous because of its easy application and long-acting characteristics. In the other study with porcine model of uncontrolled hemorrhagic shock conducted by Raedler et al [9], for evaluating the effects of vasopressin vs an equal volume of saline placebo vs fluid resuscitation on hemodynamic variables and short-term survival were shown, vasopressin did not cause further blood loss (vasopressin vs saline placebo vs fluid resuscitation 10 minutes after intervention). In our study, terlipressin was found to be advantageous for the fluid resuscitation, survival rate, and need for fluid as applied with LR to the rats with hemorrhage because of uncontrolled liver injury compared with the control group. The rats in the terlipressin group survived longer than those in the control group, and they also needed less fluid. Only 2 of the rats in the other 2 groups survived for more than 30 minutes, whereas 5 rats in terlipressin group survived longer than 30 minutes. These figures were not statistically significant between groups, which were com- posed of 7 rats each. However, the experimental animal ethics committees do not permit the use of more experimen- tal animals for ethical reasons. Therefore, we did not have the opportunity to obtain statistically significant results by increasing the number of experimental animals. Neverthe- less, the survival rate in the terlipressin group was 2.5 times greater than that in the control and LR groups.

With terlipressin application, a significant increase in the MAP was recorded (after, on average, approximately 4.5 minutes) in rats after liver injury. This increase continued for no more than 25 minutes. Thus, we hypothesize that intravenous infusion may be more effective than giving a single-dose bolus.

Vasopressin and terlipressin increase vagal tonus and decrease sympathetic tonus, leading to bradycardia. In a study by Oberti et al [21], terlipressin significantly decreased HR. In a study by Asfar et al [22], this effect was obvious after the administration of high-dose terlipressin. In our study, the HR significantly decreased in the terlipressin group at the 5th, 10th, 15th, and 35th minutes. The heart rate was significantly lower in the 20th minute in the control group, but no significant variation was observed during the follow-up. This outcome may be associated with the high- dose administration of terlipressin. We think that different doses of terlipressin and administration of terlipressin as an infusion may eliminate this side effect in future studies.

In updated guidelines for trauma, it is specified that base deficit and/or lactate levels may be beneficial for the determination of the presence or severity of shock [23]. The serial measurement of these parameters may be used for the evaluation of the responses to treatment. In our study, when the levels of lactate were compared at the end of the experiment, no significant difference was observed between groups. Likewise, no significant difference between the pH levels in the groups was observed at the end of the experiment. Similarly, when the pO₂ and pCO₂ values in groups were compared at the end of the experiment, no statistically significant result was found. In previous studies by Raedler et al and Asfar et al, vasopressin and terlipressin, respectively, increased the MAP but did not change lactate levels. No significant improvement in the lactate levels and blood gases was observed in our study, but at the same time, no distortion occurred compared with the control group. Despite the positive effects of terlipressin, no improvement was found in the base deficit, arterial pH, and lactate levels, which were used for the evaluation of the sufficient perfusion in trauma resuscitation in the control and LR groups. This result may be associated with the failure to fully perfuse the tissue. However, further studies are required to prove this hypothesis.

A single-dose bolus of terlipressin is administered in clinical practice, and this application is repeated every 6 hours. In this study, we administered a 50 ug/kg bolus dose of terlipressin. There has never been a previous study in which terlipressin was administered in cases of trauma. Nevertheless, the experimental study conducted by Asfar et al revealed that high doses such as 20 to 50 ug/kg lead to a greater increase in blood pressure compared with low doses and lead to a decrease in aortic blood flow and intestinal perfusion [22]. This effect reduces bleeding and the need for fluid in the treatment of abdominal trauma. Therefore, high- dose administration was chosen for our study. To determine the dose at which terlipressin is most active and causes

minimum adverse effects, different doses should be tested and compared.

In this hemorrhagic shock model, terlipressin improved vital signs along with the application of fluid resuscitation with only crystalloids. This drug did not lead to a significant increase in abdominal hemorrhage. The short-term survival rate in the terlipressin group increased, although this difference was not statistically significant. In this group, compared with the LR group, the MAP increased, whereas the need for fluid decreased. This result is similar to that obtained in the study by Raedler et al, who examined the effectiveness of vasopressin in treating uncontrolled hemor- rhage because of liver injury in pigs. In that study, hemorrhage did not increase in the vasopressin group compared with the control group, but it increased in the group that was administered normal fluid [9]. Because of its easy administration and few adverse effects, terlipressin is advantageous over vasopressin for this indication. In addition, vasopressin is still not an easily accessible drug in many countries, including this one.

Conclusion

This experimental method, in which we examined the effectiveness of terlipressin in hemorrhage due to liver injury, proves the effectiveness of terlipressin application during the presurgical period. In cases of hemorrhage due to uncontrolled liver injury, the need for liquid and the survival rate in the terlipressin group were higher compared with those in the LR group and control group. We speculated that terlipressin may help to reduce abdominal hemorrhage in serious liver injuries and ensure preservation of vital functions during the presurgical period.

Limitations

One limitation of our study is the difficulty of extrapolating our results to humans. Also, the short observation does not allow conclusions for the clinical setting. In addition, we did not find a statistically significant difference in the survival rates between the terlipressin group and the other groups. A very large number of animals are required to calculate statistically analysis in survival rates.

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